Apparatus for subjecting cylindrical members to heat treatment



April 20, 1943. wl'LsoN Erm. 2,317,009

APPARATUS FOR SUBJECTING CYLINDRICAL MEMBERS TO HEAT TREATMENT April 20, 1943. |...--wu soN Erm. 2,317,009

APPARATUS FOR SUBJECTING CYLINDRICAL MEMBERS T0 HEAT TREATMENT Filed June l0, 1941 2 Sheets-Sheet 2 mawugx, ai/MMM propriately designing the Patented Apr. 20, 1943 Arraas'rus ron. swacrma runnin- 'maar CAL T Dee Wilson and ohio, assilnors tion, Cleveland HEATTBEA Floyd Olmstead, I(ilevelnml, to Lee Wilson 'Sales Corpora- Ohio, a corporation of Ohio primissime 1o. 1941, semi No. :sues

(CL zes-'zr Claims.

This invention relates to a method and apparatus for progressively heating small objects and is of particular value in the metallurgical processing of articles such as shells, wrist pins or.

like objects which are either cylindrical or substantially so and therefore capable of rolling motion.

The heating of small articles has heretofore been attended with considerable difficulty from the standpoint of handling and more so in respect to the requirement that all the articles of a given batch be subjected to a uniform processing. We have invented a novel-method and apparatus greatly simplifying the handling of small articles during processing and insuring that each article is subjected to the same processing conditions as all other articles.

In a preferred embodiment and practice of our invention, we provide a pair of elongated sup ports, preferably cylindrical or substantially so, disposed in closely spaced relation and mounted for rotation about their own axes. We arrange to supply heat to the articles on the supports, preferably from the interior thereof and rotate both. supports in the same direction. The articles to be processed are delivered into the groove between the adjacent supports and are caused to rotate by their frictional contact therewith. The supports are preferably tilted so that the articles progress therealong by gravity. By apsupports and controlling the amount of heat supplied to the articles traversing them, a wide variety of processing operations may be carried out.

Further novel features and advantages of the invention will be madel appanent during the course of the following detailed description and explanation which refer to the accompanying drawings illustrating the preferred embodiment and practice outlined above. In the drawings,

Fig. 1 is a longitudinal vertical section through a heating apparatus or furnace according to our invention:

Fig. 2 is a partial plan view thereof with parts omitted; line I-I, of Fig. 2, indicates the plane on which the section shown in Fig. 1 is taken;

Fig. 3 is a transverse section taken along line III--III of Fig. 1; and

Fig. 4 is a similar section taken along IV-IV.

Referring in detail to the drawings, the apparatus of our. invention includes a refractorylined enclosure or furnace I l. The furnace Il has a bottom Il, side walls I2, end walls Il and a roof I4 composed of fire-brick and thermalinsulating brick disposed within sheathing plates nace Il in closely spaced,

Il secured to structural frame members I6', Il and II. Adjacent one end, supporting'legs I9 are secured to the frame members I1. The legs II are provided with rocker feet 28. Adjacent.v to the other end of the furnace, an adjustable support is provided in the form of a jack screw 2|. A cross beam 22 is disposed betweenthe members I1 and the jack screw 2| and a similar beam 23 extends between thevlegs I! and is secured thereto,

Cylindrical supports 24, preferably in the form of metal tubes, extend longitudinally of the furparallel relation, and have reduced end portions 2l and 2B projecting through suitable openings in theend walls I3. The spaces between the reduced end portions of the tubes and the furnace walls are closed by packing glands 2l and 28. l

The tubes 24 have journal portions on the reduced ends thereof which are received in bearings 28. The bearings are carried on cross channels 3l extending between the frame members I1. Driven sprockets 3| are secured to the reduced end portions 2! of the tubes 24. 32 trained over the sprockets 3l traverses a driving sprocket 32 on the low speed shaft of a motor-redicer unit 34. By lthe arrangement shown, operation of the unit 34 causes the tubes 24 to be driven in the same direction, i. e., either clockwise or counter-clockwise.

The tubes 24 are heated interiorly. While any convenient form of heating may be employed I prefer to utilize burners 25 projecting into the reduced end portions 2i of the tubes, for supplying fuel for combustion within the tubes 24 to heat them by direct contact of the combustion gases therewith. The burners 25 are connected to a manifold 30 through manually adjustable control valves 31. A fuel supply pipe 3l connects the manifold 36 to a suitable source of fuel. v

Air for supporting combustion within the tubes 24 is supplied to the latter from an air chest 39. The reduced ends 2i of the tubes 24 extend through a side wall of the chest 39 and have a rotatable connection thereto sealed by rings 40. An air supply pipe 4I extends from the chest 39 to a suitable source of air under pressure such as a motor-driven blower. Valve plates 42 are adjustably mounted in the chest '39 and overlie the openings through which the reduced ends 2l of the tubes 24 extend whereby they control the volume of air flowing from the chest into the several tubes.

It will'be understood that when fuel is supplied A chain through the burners and air is maintained at suitable pressure in the chest Il. the valve plates 42 being appropriately positioned, the resulting combustible mixture delivered to the interior of the tubes may be ignited at the discharge end thereof whereupon combustion continues within the tubes so long as the supply of air and fuel is maintained. The combustion gases traversing the tubes 24 heat them quickly to a high temperature whereby the'articles being processed are in turn heated by direct contact with the exterior of the tubes.

The reduced ends 24 of the tubes 24 extend into an exhaust box 43 and have a rotatable connection therewith, the latter being sealed by rings 44. 'I'he box 43 is connected to a stack or other suitable outlet for spent combustion gases.

The articles, for the processing of which our invention is particularly adapted, are indicated at 45, and as shown, are cylindrical and relatively short. The articles are delivered into the grooves between adjacent tubes 24 by delivery chutcs 4I extending from a magazine shown diagrammatically at 41 having a removable cover 41A, through the adjacent end wall i3 of the furnace Il. The magazine and chute are charged at intervals, the magazine being kept closed between charging operations. As indicated in Fig. 1, the furnace is bodily tilted at a slight angle to the horizontal by appropriate adjustment of the jack screw 2|. This adjustment of the furnace causes the articles 45 to travel longitudinally of the tubes 24 as the latter are rotated. 'I'he articles themselves are similarly rotated because of their frictional contact with the tubes, the direction of the rotation of the tubes and articles being indicated by arrows in Fig. 4. y Discharge chutes 48 are positioned to receive the articles after they have traversed the length of the central portion of the tubes 24. The chutes 4l extend downwardly through one end wall of the furnace il and deliver the articles into a quenching bath 40. The reduced ends 25A and 2l of the tubes 24 are connected to the central portions of the latter by frusta-conical sections When the articles reach the sections Il of the tubes 24. the leading end drops downwardly because of the divergence between the walls of the adjacent tubes, thereby permitting the articles to fall directly into the mouth of the chutes 44. Successive articles are separated by this opertion, by the interval between the discharge of one and the approach of the next to the discharge position. 'I'his avoids bumping of one part by another and the damage which might result, particularly if the articles are threaded.

A conveyor li has its lower .end disposed in the bath 4| below the chutes 4l and is effective to carry the articles delivered therethrough unwardly and out of the bath to a discharge chute 52. The conveyor 5| may conveniently be of the apron type, composed oi' cross slats secured to endless belts or chains and having flights 53 thereon. Guides 54 and i! determine the path oi' the lower and upper runs of the conveyor respectively. The travelling element of the conveyor is trained around sheaves Il and Il.

The conformation of the chute 4I delivers the articles to the conveyor Il in a position the reverse of that which they occupy on the supports 24. This is particularly desirable if the articles are hollow since it facilitates drainage of the quenching fluid asv the articles are removed from the bath.

It will be apparent from the foregoing description and explanation that the invention provides a method and apparatus for uniformly heating rollable articles by direct contact, which are simple in operation and construction and relatively inexpensive to construct and maintain. It will be evident that since the articles being processed are constantly rotated in contact with the cylindrical heating tubes, heat is delivered substantially uniformly over the exterior oi the articles and each article is subjected to precisely the same heating effect as all the others, assuming that the tubes 24 are driven at a constant speed, that the ming rate of the burners is not changed and the angle or inclination of the tubes remains the same. Variations in any 'of these factors may be utilized to control the nnal temperature to which the articles are raised. The angle or inclination of the tubes is preferably adjusted so that the travel of the articles thereon will be relatively slow, thus insuring a gradual heating-up. By adjusting the slope and speed of the supports 24, an infinitely variable speed of travel of the articles therealong is obtainable. It will be apparent that the lower end of the delivery chute 4B high temperature so that the heating of the articles commences before they are delivered onto the tubes 24.

A further advantage of the invention is that the articles more unidirectionally through the apparatus in a continuous stream. The thermal emciency of the method and apparatus is quite high because of the intimate contact of the work pieces or articles being processed with the supporting tubes 24, and the heating of the articles is rapid as well as uniform. Another advantage is that the work pieces are not subject to contact with the combustion gases. This permits the use of special atmospheres in the furnace il, e. g., a non-oxidizing or reducing atmosphere in case bright annealing is being carried on. The packing glands 21 and 2l prevent loss of such special atmosphere by way of the holes in the furnace walls through which the ends of the tubes project. The articles t the chute 4I fairly closely and the magazine 41 is normally closed. The chute 4I discharges under the surface of the quenching bath. Loss of the special atmosphere through the feed and discharge chutes is thus limited or prevented.

A furnace according to our invention may be designed with any desired number of supporting tubes. The arrangement shown in the drawings, utilizing three tubes, has the maximum capacity per tube, since the middle tube cooperates with each of the outside tubes in supporting a row of work pieces.

Although we have illustrated and described in detail a preferred embodiment of our invention, it will be recognized that changes in the construction and operation disclosed may be made without departing from the spirit of the invention or the scope of the appended claims.

Instead of delivering a combustible mixture to the interior of the supporting tubes and causing combustion therein, the tubes may be otherwise heated interiorly, as by electric resistance heaters, or heat maybe supplied on the outside of the tubes by burners discharging into the interior of the furnace or electric resistance heat-A ing element Vsuitably mounted therein. Instead of the tubes will normally be at a relatively 24, the elongated supports for the articles being processed may be solid. They may, furthermore, be composed of refractory material instead of metal.

The gravity feed of the articles along the support may be dispensed with and any suitable form of feed means employed which is capable of operating between the tubes 24 or other supports similar thereto. In the processing of spherical articles such as balls, it is undesirable to have the tubes slope downwardly toward the discharge end because this would permit the balls to roll freely down the supports in such a short time that proper heating thereof could not be obtained. In such cases, the supporting tubes may be tilted upwardly toward the discharge end by lowering the jack screws 2l and the articles pushed along the tubes either by pressure applied to the rearmost article in the magazine and feed chute or by a special travelling feed mechanism. For example, a spiral flight on one of the tubes would suffice to advance the articles therealong in a positive manner at a predetermined rate. A travelling feed chain is another example of means suitable for urging several articles along the tubes if they are tilted up toward the discharge end or restraining them from too rapid passage along the tubes if they are tilted downwardly toward the discharge end.

It will be understood, furthermore, that the supporting tubes 24 need not be precisely parallel nor truly cylindrical. Tapered rolls may be useful for certain types of articles and the rolls may be set at a slight angle as well as exactly parallel.

It will be evident that the invention may be used for the heating of a wide variety of articles either spherical, truly cylindrical, or irregularly shaped, i. e., tapered, headed or the like as are many forms of pins, screws, rivets, etc.

We claim:

1. A heating furnace comprising a refractorybetween said tubes near one end thereof and a y discharge chute near the other end of the tubes adapted to receive the pieces after they have traveled along the tubes.

2. A heating furnace comprising a refractorylined enclosure, a pair of tubes extending through the furnace, journal bearings outside the furnace engaging the ends of the tubes and supporting them rotatably in closely spaced, generally parallel relation, and burners firing into said tubes through one end thereof.

3. A heating furnace comprising a refractorylined enclosure, a pair of tubes extending through said enclosure in closely spaced, generally parallel relation, means mounting said tubes for rotation about their own axes, means for driving said tubes, means for heating said tubes, and means for bodily tilting said enclosure about an axis transverse to the axis of said tubes to cause work pieces placed in the groove between said tubes near one end thereof to travel along said tubes as the latter are rotated.

4. A heating furnace as defined by claim 3 characterized by said tilting means including supporting legs with rocker feet near one end of the enclosure, and an adjustable support for other end of the enclosure.

5. Apparatus for conveying articles through a heating zone comprising a pair of substantially cylindrical supports mounted for rotation in said zone, said supports being truste-conical at least adjacent one end whereby the increasing divergence between the surfaces of the supports at said end facilitates the discharge of articles moving along said members.

LEE wnsoN. FLOYD oms'rEAD. 

